[hpsdr] [Hpsdr] Call for Comments - ALEX

[CT1IZU]

> >
> > For the rx filters above 30MHz something like the Toko MC120 is good .
They
> > are easy to adjust and have a good Q. On the TX side on 6 up to around
10W
> > the Toko S18 with an alloy core is ok.
> >
> > Shel CT1IZU

> As far the TOKO coils with ferrite core, the data we have seen suggests
> poor IP3 performance,
> so we are likely to stay with the T-50 toroids or go with air wound coils.

Yes read diagram twice then comment. I had forgotten about the 33/55 LPF in
at all times. In front of the 6Mtr LNA though as a BPF the MC120  may still
be appropriate. I use them in two hombrew tranceivers for 6 and 4 meters
with 4 pole bottom inductor coupling and 17dBm mixers, so far without
issues.

Air coils sound appealing but I wonder how easy it will be get tight control
of the inductances on the 33 or 55Mhz filters? Would it be better to use  a
filter where the meshes are tuned by a small trimmer cap?


Shel  CT1IZU



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